Well, the state troops would just be the garrison. The actual person on the controls would be an expert—the question is, who's managing, administrating, and paying for it? If we can trust soldiers around the Emperor or the Imperial armouries or the hundreds of other strategic assets they protect without falling to chaos, we can trust them with a nexus.
The only reason beastmen or skaven are not living here already is because the path is hard to find—or rather, was hard to find, considering we just cut a new path into it. The clock is ticking and we need to find something to fill the space, or someone else will. Having state troopers links it in to the wider military of the Empire, which has logistics chains and reinforcements and regular communications.
Hell, remember when Abel nearly fired Kasimir because he was recruiting the wrong types of priests to support his armies? These aren't just thugs with swords, it's a fully staffed military with appropriate, high level, auxiliary support, and the discipline and training to do their jobs—which would be to protect the Nexus at any cost.